While I am not yet a parent, I do have strong feelings about this topic. When I was in high school, one of my friends was accidentally shot and killed by another young person who was playing with a gun.
I grew up afraid of going near a gun and I probably wouldn't know what to do with one if I had it in my hands. There were no fake guns in my household (except for waterguns) and neither me or my brother played gun-related games. I don't know where these kids are getting guns, but if there was a gun lying next to me, I wouldn't touch it except if my life depended on it.
I think toy guns reduces the seriousness of real ones and doesn't allow kids to think of the consequences of playing like that. I won't allow my children to play with toy guns, and I think they should be banned. It may not be my perogative what other people let their children play with, but it is my business if my child gets shot by some kid who's parents didn't teach them the difference between a real gun and a fake one.